Integrated circuit memory devices are typically formed as volatile memory devices that lose stored data after power interruption or nonvolatile memory devices that retain stored data after power interruption. Many of these nonvolatile memory devices may utilize non-volatile memory cells having material properties that support nonvolatile data storage. For example, some nonvolatile memory cells may utilize phase-changeable materials, such as chalcogenide materials, to store a logic state (e.g., “0” or “1”) of the memory cell. These memory cells are typically classified as phase-changeable random access memory (PRAM) cells. In some of these memory cells, a switch (e.g., diode) is provided in series with a phase changeable material. To achieve high levels of integration, this switch may be formed using a vertical stack of layers. Some examples of conventional PRAM cells are disclosed in US 2008/0078984 to Park et al., entitled “Semiconductor Device and Method of Fabricating the Same;” and in US 2008/0113469 to Eun et al., entitled “Methods of Fabricating a Semiconductor Device Including a Self-Aligned Cell Diode.”